1. Field of the Invention
The present invention relates to an inkjet device capable of preventing cohesion and sedimentation of ink in an ink reservoir.
2. Related Art
There has been known an inkjet printer that includes an inkjet head formed with a plurality of nozzles through which ink droplets are ejected onto a recording medium to form images thereon. There are also provided various types of inks, including dye-based inks, pigment-based inks, and polymeric inks, that can be used in such an inkjet printer. Pigment-based inks have a problem in that the pigments in the ink can easily cohere with each other or settle out from the liquid base. Polymeric inks have a problem in that over time the molecular-weight distribution can increase because of molecular coupling. When these problems arise, printing results can be erratic and the ink nozzles can become clogged.
In order to overcome these problems, there has been proposed to provide stirrer bares, such as magnetic stirrers, that a main unit can drive without contact the same, in the ink tank of inkjet printers in order to agitate the ink in the ink tank.
However, merely stirring up the ink does not sufficiently disperse pigments and molecular materials, so that problems, such as pigment sedimentation and cohesion, cannot be completely solved.
It is an object of the present invention to overcome the above-described problems and to provide an inkjet device capable of preventing problems, such as pigment sedimentation, and pigment cohesion, and increase in molecular-weight distribution.
In order to overcome the above and other objects, there is provided an inkjet device including an inkjet head that ejects ink droplets, an ink reservoir that holds ink, an ultrasonic vibration unit that applies ultrasonic vibration to the ink in the ink reservoir, a condition judgment unit that judges whether a certain condition is established, and a vibration control unit that, when the condition judgment unit judges that the certain condition is established, controls the ultrasonic vibration unit to apply ultrasonic vibration to the ink.